1. Ocean plants Maia McGuire Florida Sea Grant Extension Agent

2. Terminology Aquatic Estuarine Freshwater Marine Emergent Floating Submerged Phytoplankton Algae Seagrass SAV (submerged aquatic vegetation) True plant

3. Phytoplankton Mostly single-celled, photosynthetic, microscopic plants DIATOMS are the most abundant type of phytoplankton—they have a silica “housing” DINOFLAGELLATES often produce toxins (and red tides!); some bioluminescesome bioluminesce

4. Activity Design and construct a plankter

5. Algae blooms Usually a response to increased nutrient levels Phytoplankton reproduce by dividing, creating high concentrations (“blooms”) Nutrient loading can be natural (upwelling) or related to runoff from land

6. Red tide Bloom of a type of dinoflagellate Algae release a chemical that goes into the water and also into the air – Causes respiratory difficulties to humans – Toxic to fish and sometimes to marine mammals

7. Red tide (cont.) Blooms form offshore in Gulf of Mexico Can bloom in any month of the year Blooms can last for weeks to months; may be lengthened by runoff from land (?)

8. Multi-cellular plants… Algae – Not considered true plants—no roots, flowers, vascular system – Often called “seaweed” – Often use holdfasts to attach to the substrate – Different groups of algae contain different types of chlorophyll – Green algae, brown algae, red algae

9. Reproduction in algae Sexual reproduction involves production of spores, which produce a gametophyte, which produces gametes

10. Green algae Contain chlorophyll a and b Examples: sea lettuce (Ulva lactuca), dead man’s fingers (Codium fragile)

11. Some make calcium carbonate skeletons

12. Brown algae Contain chlorophyll a and c Includes Sargassum seaweed

13. Red algae Contain chlorophyll a Source of agar, carrageenan (used in many food products Few have common names Often finely branching

14. Calcareous red algae Often found on coral reefs—help “cement” the reef surface

15. Activity Pressing seaweed

16. Seagrasses Fully submerged marine plants; true angiosperms – True roots, vascular system, flowers – Reproduce asexually using rhizomes 6-7 species; 3 common – Turtle grass, Shoal grass, Manatee grass – Star grass, Paddle grass, Johnson’s seagrass, – Widgeon grass (freshwater grass with high salinity tolerance)

17. http://fmel.ifas.ufl.edu/habitat/seagrass_parts.shtml

18. Thalassia testudinum Turtle grass Largest and most robust of Florida’s seagrasses Flat, wide (4-12 mm) leaf blades (10-35 cm in length) 2-5 leaves per shoot Forms extensive meadows

19. Halodule wrightii Shoal grass Early colonizer of disturbed areas or areas too deep or shallow for other seagrasses – Tolerates wide range of T, S Leaves flat (1-3 mm wide), 10-20 cm long Tips of leaves have 2-3 points

20. Syringodium filiforme Manatee grass Leaves are round (like spaghetti); 1-1.5 mm in diameter; length varies but can reach 50 cm Commonly found mixed with other seagrasses or in small monospecific patches

21. Halophila engelmanni, H. decipiens, H. johnsonii Relatively sparsely distributed Paddle-shaped leaf blades Johnson’s seagrass is listed as a threatened species

22. Ruppia maritima Widgeon grass Often found alongside Halodule in areas of lower salinity Important food for waterfowl Primarily a freshwater plant

23. Seagrass distribution Thalassia testudinum Syringodium filiforme Halodule wrightii Halophila engelmanii Halophila decipiens Halophila johnsonii

24. Ruppia maritima distribution

25. Seagrass biology Growth – Thalassia blades can grow as much as 1 cm/day – Growth is slowed by cooler temperatures – Extremes in temperatures (hot or cold) can kill leaf blades – Optimal temperature range 20-30° C – Optimal salinity range 24-35 ppt – Extensive seagrass beds not found deeper than 10-15 m (light and pressure are both factors)

26. Zonation Halodule grows in shallowest water and has highest tolerance to exposure Thalassia is most dominant; forms large meadows in waters up to 10-12 m deep Syringodium forms meadows in deep water (up to 15 m) Halodule and Halophila can grow in even deeper water, but sparsely

27. Productivity Highly productive ecosystems Important food source, for grazers and as detritus

28. Seagrasses provide habitat Many species of fish Molluscs (e.g. scallops, snails) Shrimp, crabs and other crustaceans Worms

29. Threats to seagrasses Physical damage – Dredging, prop scars/blowouts Eutrophication Salinity stress Temperature stress

30. Mangroves Emergent plants Very salt-tolerant Have adaptations to deal with salt and wave action Occur in zones Three species in Florida

31. Red mangrove Rhizophora mangle Has prop roots to stabilize tree

33. Black mangrove Avicennia germinans Has “pneumatophores” (breathing roots) Salty leaves

35. White mangrove Laguncularia racemosa

36. Ocean stewardship Read “A new home for an old friend” to teach kids that aquarium plants should not be dumped into ponds or the ocean http://www.usc.edu/org/seagrant/caulerpa/index.html